${21} \div {3} = {?}$
Explanation: If we split ${21}$ circles into $3$ equal rows, how many circles are in each row? ${3}$ ${\color{#29ABCA}{1}}$ ${\color{#29ABCA}{2}}$ ${\color{#29ABCA}{3}}$ ${\color{#29ABCA}{4}}$ ${\color{#29ABCA}{5}}$ ${\color{#29ABCA}{6}}$ ${\color{#29ABCA}{7}}$ ${2}$ ${\color{#29ABCA}{8}}$ ${\color{#29ABCA}{9}}$ ${\color{#29ABCA}{10}}$ ${\color{#29ABCA}{11}}$ ${\color{#29ABCA}{12}}$ ${\color{#29ABCA}{13}}$ ${\color{#29ABCA}{14}}$ ${1}$ ${\color{#29ABCA}{15}}$ ${\color{#29ABCA}{16}}$ ${\color{#29ABCA}{17}}$ ${\color{#29ABCA}{18}}$ ${\color{#29ABCA}{19}}$ ${\color{#29ABCA}{20}}$ ${\color{#29ABCA}{21}}$ ${21} \div {3} = {7}$